{"product_id":"moose-racing-exhaust-gasket-kit-yamaha-yz250-yz250x-0934-5321","title":"Moose Racing - Exhaust Gasket Kit - Yamaha YZ250X \u0026 YZ250","description":"\u003ch1\u003eMoose Racing Exhaust Gasket Kit for Yamaha YZ250X \u0026amp; YZ250 Two Strokes\u003c\/h1\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"1\"\u003e\u003cspan\u003eThe Moose Racing Exhaust Gasket Kit (0934-5321) is an OEM-replacement cylinder-to-pipe sealing and retention kit engineered for 2001+ Yamaha YZ250 and YZ250X two-stroke motorcycles.\u003c\/span\u003e\u003cspan\u003e Two-stroke expansion chambers endure extreme exhaust gas temperatures and constant high-frequency engine vibration.\u003c\/span\u003e\u003cspan\u003e Over time,\u003c\/span\u003e\u003cspan\u003e thermal cycling hardens and flattens the dual rubber manifold O-rings while stretching the exhaust tension springs.\u003c\/span\u003e\u003cspan\u003e Once the seal degrades,\u003c\/span\u003e\u003cspan\u003e unburned two-stroke oil (\"spooge\") weeps onto the cylinder and front engine cases,\u003c\/span\u003e\u003cspan\u003e and ambient air is drawn into the exhaust port during scavenging pulses—disrupting backpressure and leaning out jetting.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"2\"\u003e\u003cspan\u003eManufactured to meet or exceed Yamaha factory specifications,\u003c\/span\u003e\u003cspan\u003e the 0934-5321 kit includes two high-temperature fluorocarbon (Viton) exhaust manifold O-rings and two heavy-duty swivel-hook tension springs.\u003c\/span\u003e\u003cspan\u003e The high-temp elastomer rings resist thermal hardening and chemical breakdown from synthetic premix oils,\u003c\/span\u003e\u003cspan\u003e while the high-tensile springs maintain consistent clamping tension between the expansion chamber collar and cylinder exhaust spigot across stock and aftermarket exhaust systems.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch4 dir=\"ltr\" data-path-to-node=\"3\"\u003eFeatures:\u003c\/h4\u003e\n\u003cul dir=\"ltr\" data-path-to-node=\"4\"\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"4,0,0\"\u003e\u003cb data-path-to-node=\"4,0,0\" data-index-in-node=\"0\"\u003eComplete Cylinder-to-Pipe Service Kit:\u003c\/b\u003e\u003cspan\u003e Includes both exhaust manifold O-rings and both tension springs needed to reseal the primary exhaust port junction.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"4,1,0\"\u003e\u003cb data-path-to-node=\"4,1,0\" data-index-in-node=\"0\"\u003eHigh-Temperature Viton O-Rings:\u003c\/b\u003e\u003cspan\u003e Fluorocarbon elastomer rings withstand sustained two-stroke exhaust temperatures and synthetic premix oil exposure without flattening or cracking.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"4,2,0\"\u003e\u003cb data-path-to-node=\"4,2,0\" data-index-in-node=\"0\"\u003eSwivel-Hook Tension Springs:\u003c\/b\u003e\u003cspan\u003e High-tensile spring steel construction with rotating swivel ends reduces harmonic vibration fatigue and prevents hook breakage.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"4,3,0\"\u003e\u003cb data-path-to-node=\"4,3,0\" data-index-in-node=\"0\"\u003eEliminates Oil Leaks \u0026amp; Air Intrusion:\u003c\/b\u003e\u003cspan\u003e Restores an airtight seal at the cylinder flange to stop black exhaust oil drips and prevent lean air leaks during exhaust scavenging.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"4,4,0\"\u003e\u003cb data-path-to-node=\"4,4,0\" data-index-in-node=\"0\"\u003eDirect OEM Cross-Reference:\u003c\/b\u003e\u003cspan\u003e Replaces Yamaha factory exhaust seals (\u003c\/span\u003e\u003ccode data-path-to-node=\"4,4,0\" data-index-in-node=\"67\"\u003e5MW-14642-00-00\u003c\/code\u003e\u003cspan\u003e) and tension springs (\u003c\/span\u003e\u003ccode data-path-to-node=\"4,4,0\" data-index-in-node=\"105\"\u003e90507-20052-00\u003c\/code\u003e\u003cspan\u003e).\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"4,5,0\"\u003e\u003cb data-path-to-node=\"4,5,0\" data-index-in-node=\"0\"\u003eUniversal Pipe Compatibility:\u003c\/b\u003e\u003cspan\u003e Fits OEM Yamaha expansion chambers as well as aftermarket two-stroke pipes (FMF Gnarly,\u003c\/span\u003e\u003cspan\u003e FMF Fatty,\u003c\/span\u003e\u003cspan\u003e Pro Circuit Works\/Platinum,\u003c\/span\u003e\u003cspan\u003e Scalvini).\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4 dir=\"ltr\" data-path-to-node=\"5\"\u003eWhat's in the Box:\u003c\/h4\u003e\n\u003cul dir=\"ltr\" data-path-to-node=\"6\"\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"6,0,0\" id=\"p-rc_31579342494b3791-85\"\u003e\u003cspan class=\"citation-175\"\u003e2x High-Temperature Viton Exhaust Manifold O-Rings (Replaces OEM # \u003c\/span\u003e\u003ccode data-path-to-node=\"6,0,0\" data-index-in-node=\"67\"\u003e\u003cspan class=\"citation-175\"\u003e5MW-14642-00-00\u003c\/span\u003e\u003c\/code\u003e\u003cspan class=\"citation-175 citation-end-175\"\u003e)\u003csup class=\"superscript\" data-turn-source-index=\"1\"\u003e\u003c!----\u003e\u003c\/sup\u003e\u003c\/span\u003e \u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"6,1,0\" id=\"p-rc_31579342494b3791-86\"\u003e\u003cspan class=\"citation-174\"\u003e2x Heavy-Duty Swivel-Hook Exhaust Tension Springs (Replaces OEM # \u003c\/span\u003e\u003ccode data-path-to-node=\"6,1,0\" data-index-in-node=\"66\"\u003e\u003cspan class=\"citation-174\"\u003e90507-20052-00\u003c\/span\u003e\u003c\/code\u003e\u003cspan class=\"citation-174 citation-end-174\"\u003e)\u003csup class=\"superscript\" data-turn-source-index=\"2\"\u003e\u003c!----\u003e\u003c\/sup\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eFitment:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ch4\u003e2016–2027 – Yamaha YZ250X\u003c\/h4\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ch4\u003e2001–2027 – Yamaha YZ 250\u003c\/h4\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eFitment Notes:\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"8,1,0\"\u003e\u003cb data-path-to-node=\"8,1,0\" data-index-in-node=\"0\"\u003eGeneration Incompatibility Warning:\u003c\/b\u003e\u003cspan\u003e Does \u003c\/span\u003e\u003cb data-path-to-node=\"8,1,0\" data-index-in-node=\"41\"\u003eNOT\u003c\/b\u003e\u003cspan\u003e fit 1999–2000 Yamaha YZ250 models (which require Moose kit \u003c\/span\u003e\u003ccode data-path-to-node=\"8,1,0\" data-index-in-node=\"104\"\u003e0934-5322\u003c\/code\u003e\u003cspan\u003e \/ Vertex \u003c\/span\u003e\u003ccode data-path-to-node=\"8,1,0\" data-index-in-node=\"123\"\u003e823140\u003c\/code\u003e\u003cspan\u003e) or pre-1999 YZ250 models.\u003c\/span\u003e\u003cspan\u003e Does \u003c\/span\u003e\u003cb data-path-to-node=\"8,1,0\" data-index-in-node=\"162\"\u003eNOT\u003c\/b\u003e\u003cspan\u003e fit YZ250F or YZ250FX four-stroke models.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"8,2,0\"\u003e\u003cb data-path-to-node=\"8,2,0\" data-index-in-node=\"0\"\u003eSilencer Coupler Note:\u003c\/b\u003e\u003cspan\u003e Services the primary cylinder-to-expansion-chamber joint; does not include the rubber pipe-to-silencer joint sleeve (Yamaha OEM # \u003c\/span\u003e\u003ccode data-path-to-node=\"8,2,0\" data-index-in-node=\"153\"\u003e3JE-14615-01-00\u003c\/code\u003e\u003cspan\u003e).\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"8,3,0\"\u003e\u003cb data-path-to-node=\"8,3,0\" data-index-in-node=\"0\"\u003eOEM \u0026amp; Aftermarket Part Number Cross-Reference:\u003c\/b\u003e\u003c\/p\u003e\n\u003cul dir=\"ltr\" data-path-to-node=\"8,3,1\"\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"8,3,1,0,0\" id=\"p-rc_31579342494b3791-89\"\u003e\u003cspan class=\"citation-171\"\u003eReplaces Yamaha OEM Exhaust Seal # \u003c\/span\u003e\u003cb data-path-to-node=\"8,3,1,0,0\" data-index-in-node=\"35\"\u003e\u003cspan class=\"citation-171\"\u003e5MW-14642-00-00\u003c\/span\u003e\u003c\/b\u003e\u003cspan class=\"citation-171 citation-end-171\"\u003e (Qty 2)\u003csup class=\"superscript\" data-turn-source-index=\"5\"\u003e\u003c!----\u003e\u003c\/sup\u003e\u003c\/span\u003e \u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"8,3,1,1,0\" id=\"p-rc_31579342494b3791-90\"\u003e\u003cspan class=\"citation-170\"\u003eReplaces Yamaha OEM Tension Spring # \u003c\/span\u003e\u003cb data-path-to-node=\"8,3,1,1,0\" data-index-in-node=\"37\"\u003e\u003cspan class=\"citation-170\"\u003e90507-20052-00\u003c\/span\u003e\u003c\/b\u003e\u003cspan class=\"citation-170 citation-end-170\"\u003e (Qty 2)\u003csup class=\"superscript\" data-turn-source-index=\"6\"\u003e\u003c!----\u003e\u003c\/sup\u003e\u003c\/span\u003e \u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"8,3,1,2,0\" id=\"p-rc_31579342494b3791-91\"\u003e\u003cspan class=\"citation-169\"\u003eCross-references Vertex \/ Winderosa Part # \u003c\/span\u003e\u003ca href=\"https:\/\/www.tmbrmoto.com\/products\/vertex-exhaust-gasket-kit-yamaha-yz250x-yz250-823139\" title=\"Shop TMBR MOTO for Yamaha YZ250X maintenance parts, tools and supplies.\"\u003e\u003cspan style=\"text-decoration: underline; color: rgb(215, 65, 35);\"\u003e\u003cb data-path-to-node=\"8,3,1,2,0\" data-index-in-node=\"43\"\u003e\u003cspan class=\"citation-169\"\u003e823139\u003c\/span\u003e\u003c\/b\u003e\u003c\/span\u003e\u003c\/a\u003e\u003cspan class=\"citation-169\"\u003e \/ \u003c\/span\u003e\u003cb data-path-to-node=\"8,3,1,2,0\" data-index-in-node=\"52\" class=\"\"\u003e\u003cspan class=\"citation-169 citation-end-169\"\u003e823139MSE\u003csup class=\"superscript\" data-turn-source-index=\"7\"\u003e\u003c!----\u003e\u003c\/sup\u003e\u003c\/span\u003e\u003c\/b\u003e \u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c!----\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e\u003cmeta charset=\"utf-8\"\u003e\u003c\/strong\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"12\"\u003e\u003cb data-path-to-node=\"12\" data-index-in-node=\"0\"\u003eO-Ring Groove Cleaning \u0026amp; Silicone Lubrication:\u003c\/b\u003e\u003cspan\u003e Before installing the new O-rings,\u003c\/span\u003e\u003cspan\u003e inspect the two internal seal grooves inside your expansion chamber collar (or cylinder spigot,\u003c\/span\u003e\u003cspan\u003e depending on pipe brand).\u003c\/span\u003e\u003cspan\u003e Baked-on carbon and two-stroke oil residue frequently pack into the bottom of these grooves,\u003c\/span\u003e\u003cspan\u003e preventing new O-rings from seating fully and causing the pipe to bind during installation.\u003c\/span\u003e\u003cspan\u003e Scrape out hardened carbon with a brass pick,\u003c\/span\u003e\u003cspan\u003e clean the grooves with \u003ca href=\"https:\/\/www.tmbrmoto.com\/products\/maxima-electrical-contact-cleaner-aerosol-72920\" title=\"Shop for Maxima contact cleaner and other motorcycle maintenance chemicals at TMBR MOTO.\"\u003e\u003cspan style=\"text-decoration: underline; color: rgb(215, 65, 35);\"\u003e\u003cstrong\u003eMaxima Electrical Contact Cleaner\u003c\/strong\u003e\u003c\/span\u003e\u003c\/a\u003e,\u003c\/span\u003e\u003cspan\u003e and seat the new O-rings cleanly.\u003c\/span\u003e\u003cspan\u003e Coat the O-rings and the cylinder exhaust flange with a thin film of \u003cspan style=\"color: rgb(215, 65, 35);\"\u003e\u003ca href=\"https:\/\/www.tmbrmoto.com\/products\/permatex-ultra-copper-maximum-temperature-rtv-silicone-gasket-maker-3oz-81878\" title=\"Shop for Permatex RTV, sealants and lubricants for proper motorcycle maintenance at TMBR MOTO\" style=\"color: rgb(215, 65, 35);\"\u003e\u003cspan style=\"text-decoration: underline;\"\u003e\u003cstrong\u003ePermatex Ultra Copper RTV (\u003c\/strong\u003e\u003c\/span\u003e\u003c\/a\u003e\u003c\/span\u003e\u003c\/span\u003e\u003cspan style=\"color: rgb(215, 65, 35);\"\u003e\u003ca href=\"https:\/\/www.tmbrmoto.com\/products\/permatex-ultra-copper-maximum-temperature-rtv-silicone-gasket-maker-3oz-81878\" title=\"Shop for Permatex RTV, sealants and lubricants for proper motorcycle maintenance at TMBR MOTO\" style=\"color: rgb(215, 65, 35);\"\u003e\u003cspan style=\"text-decoration: underline;\"\u003e\u003cstrong\u003e\u003ccode data-path-to-node=\"12\" data-index-in-node=\"623\"\u003e81878\u003c\/code\u003e\u003c\/strong\u003e\u003c\/span\u003e\u003c\/a\u003e\u003c\/span\u003e\u003cspan\u003e\u003cspan style=\"color: rgb(215, 65, 35);\"\u003e\u003ca href=\"https:\/\/www.tmbrmoto.com\/products\/permatex-ultra-copper-maximum-temperature-rtv-silicone-gasket-maker-3oz-81878\" title=\"Shop for Permatex RTV, sealants and lubricants for proper motorcycle maintenance at TMBR MOTO\" style=\"color: rgb(215, 65, 35);\"\u003e\u003cspan style=\"text-decoration: underline;\"\u003e\u003cstrong\u003e)\u003c\/strong\u003e\u003c\/span\u003e\u003c\/a\u003e\u003c\/span\u003e before sliding the pipe into place—installing dry O-rings can cause them to pinch,\u003c\/span\u003e\u003cspan\u003e roll out of the groove,\u003c\/span\u003e\u003cspan\u003e or tear.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"13\"\u003e\u003cb data-path-to-node=\"13\" data-index-in-node=\"0\"\u003eSwivel-Hook Spring Orientation \u0026amp; Safe Installation:\u003c\/b\u003e\u003cspan\u003e Always install and remove exhaust springs using a dedicated T-handle spring puller tool rather than pliers or flathead screwdrivers,\u003c\/span\u003e\u003cspan\u003e which can slip and possibly puncture radiator cores.\u003c\/span\u003e\u003cspan\u003e Orient the rotating swivel end of each spring toward the cylinder head hook so the spring can pivot freely under high-frequency two-stroke vibration without fatiguing or snapping the hook loop.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"14\"\u003e\u003cb data-path-to-node=\"14\" data-index-in-node=\"0\"\u003eStress-Free Expansion Chamber Alignment:\u003c\/b\u003e\u003cspan\u003e Two-stroke pipes undergo substantial thermal expansion and frame flex on the trail.\u003c\/span\u003e\u003cspan\u003e Always hook up the two cylinder flange springs and slide the stinger pipe into the rubber silencer coupler \u003c\/span\u003e\u003cb data-path-to-node=\"14\" data-index-in-node=\"232\"\u003ebefore\u003c\/b\u003e\u003cspan\u003e tightening the two frame isolator mounting bolts.\u003c\/span\u003e\u003cspan\u003e Leaving the frame bolts loose until the pipe settles naturally into its resting position prevents side-loading the new O-rings and eliminates premature cracking of pipe mounting tabs.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp dir=\"ltr\" data-path-to-node=\"15\"\u003e\u003cb data-path-to-node=\"15\" data-index-in-node=\"0\"\u003eMaintenance Interval:\u003c\/b\u003e\u003cspan\u003e Replace both exhaust O-rings and tension springs whenever installing a new expansion chamber,\u003c\/span\u003e\u003cspan\u003e performing a top-end piston service,\u003c\/span\u003e\u003cspan\u003e or noticing black oil residue misting around the cylinder head flange.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cbr\u003ePart Number: \u003cmeta charset=\"utf-8\"\u003e\u003c\/span\u003e0934-5321\u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e","brand":"Moose Racing","offers":[{"title":"Default Title","offer_id":44630738796709,"sku":"MOOSE-GSKT-EXH-YZ250X","price":19.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/5720\/1317\/files\/Moose_Racing_Exhaust_Gasket_Sprint_Kit_YZ250X_0934-5321.jpg?v=1794683008","url":"https:\/\/www.tmbrmoto.com\/products\/moose-racing-exhaust-gasket-kit-yamaha-yz250-yz250x-0934-5321","provider":"TMBR MOTO","version":"1.0","type":"link"}